SERVICES

Custom Recombinant Proteins

Recombinant proteins expressed in your chosen bacterial, insect, or mammalian platform, to customer-specified sequence, tag, or domain construct. Optional matched rabbit polyclonal antibody from the same production run.

Request a quote See workflow

Overview

Expression platform selection is a project decision the customer makes — TPB works in bacterial (E. coli), insect (Sf9/baculovirus), or mammalian (HEK293/CHO) systems. For many proteinases and inhibitors, mammalian-type glycosylation and correct disulfide pairing are required for folding, activity, and biological relevance, so mammalian expression is often the right choice for these targets. If a simpler bacterial construct is preferred, or the target has already been validated in that format, we accept the specification and proceed accordingly. Every project follows the same codon-optimization-through-QC workflow used for TPB catalog proteins, so the quality benchmarks — SDS-PAGE purity, endotoxin control, and activity verification where applicable — are identical to what ships in catalog lots.

Construct flexibility is a practical requirement for structural and mechanistic studies. A researcher characterizing the catalytic domain of a matrix metalloproteinase, for example, may need a His-tagged active-site mutant at milligram scale — a specification that falls outside catalog offerings but within the scope of this service. Point mutants, truncations, and domain fusions are all handled at the construct-design stage, with sequence verification confirming the final clone before scale-up begins.

TPB's matched-pair option addresses a common bottleneck: researchers who generate a novel recombinant often need a corresponding detection tool. Because the antibody immunogen is the same construct produced here, epitope coverage and cross-reactivity profiles are directly traceable to the protein's expressed sequence. The antibody production track runs in parallel with protein scale-up, avoiding sequential project delays. This combination — 32 years of proteinase biology, flexible expression platform choice, and in-house antibody production — defines what distinguishes TPB's custom protein service from general-purpose contract expression.

Scientists working with laboratory test tubes

Workflow

Construct design & codon optimization — Sequence review, domain boundary confirmation, tag placement, and codon optimization for your chosen expression system. ~2 weeks
Cloning & small-scale expression test — Gene synthesis, cloning into expression vector, transient transfection at small scale, and conditioned-medium/lysate analysis to confirm expression. ~3 weeks
Scale-up production — Expi293-style transient transfection at the quantity required to meet target yield (typical deliverable: 0.5–5 mg purified protein). ~3 weeks
Affinity purification & tag cleavage (if requested) — Capture via His, FLAG, or GST affinity resin; protease cleavage and secondary purification for tag-free protein. ~2 weeks
QC panel — Reducing/non-reducing SDS-PAGE, LAL endotoxin assay (<0.1 EU/µg specification), and activity assay for catalytic-domain constructs where a validated substrate assay is applicable. Included in step 4–5 window
Delivery — Protein shipped at researcher-specified buffer and concentration with full CoA documentation. Total typical timeline: 10–12 weeks from project initiation

Optional matched antibody track: rabbit polyclonal immunization against the same construct initiates in parallel at step 3 and adds approximately 18 weeks to deliver antiserum/affinity-purified antibody.

Deliverables

Purified recombinant protein at researcher-specified quantity (typical range 0.5–5 mg)
Certificate of Analysis (CoA) including expressed sequence, tag configuration, and lot-specific QC results
Sequence-verified construct confirmation (sequencing data included)
SDS-PAGE gel image (reducing and/or non-reducing, as applicable)
LAL endotoxin test result (<0.1 EU/µg specification)
Activity assay data for catalytic-domain constructs where a validated substrate assay is applicable
Storage and stability recommendations for the specific construct
If matched-antibody option selected: affinity-purified rabbit polyclonal with its own CoA and Western blot validation data

Options

Affinity tag: His (6×His N- or C-terminal), FLAG, GST, or tag-free (protease cleavage post-purification)
Construct type: Full-length, domain construct (e.g., catalytic domain only), or custom truncation
Point mutants: Single or multiple substitutions — for example, active-site mutants for structural or mechanistic studies
Expression scale: Small-scale expression test through milligram-scale production (up to 100 mg total; see scope)
Matched antibody (optional add-on): Rabbit polyclonal raised against the same expressed construct, run as a parallel 18-week track

Timing and pricing

Typical project duration is 10–12 weeks from signed project agreement to shipment, covering construct design through QC and delivery. The optional matched rabbit polyclonal antibody track adds approximately 18 weeks and runs in parallel with protein scale-up where possible.

Pricing is project-based. A written quote is provided after review of the target sequence, construct specification, required quantity, and QC requirements. Contact TPB with your sequence and specification to receive a scoped quote.

Scope

No GMP or therapeutically intended proteins — this service is Research Use Only (RUO)
No production runs exceeding 100 mg — inquiries requiring larger scale should seek a dedicated CDMO
No cell-based or in vivo functional assays — QC is limited to the panel described (SDS-PAGE, endotoxin, in-vitro activity where applicable)

Frequently asked questions

What information do I need to submit to get a quote?

Provide the target protein name, species, UniProt accession or sequence, the specific construct boundaries or mutations required, your preferred affinity tag (or tag-free), and the minimum quantity needed. If you want the matched-antibody option, indicate that at the outset so both tracks can be scoped together.

How is the project priced — is there a per-milligram rate?

Pricing is project-based, not per-milligram. Each quote reflects the complexity of the construct, the scale-up volume required to reach the target yield, and whether optional services such as tag cleavage or matched antibody are included. A written quote is issued after specification review.

Which expression system should I choose — bacterial, insect, or mammalian?

TPB expresses in E. coli, Sf9/baculovirus, and mammalian systems (HEK293/CHO) — the choice is yours. For many proteinases and inhibitors, bacterial expression produces insoluble or misfolded protein that requires refolding, which frequently compromises activity. Mammalian expression provides glycosylation, correct disulfide processing, and proprotein cleavage where relevant — the timeline is longer, but the probability of receiving a functional, correctly-folded protein is higher for these targets. That said, if your target expresses well in E. coli or you've already validated it in bacterial format, we work in whichever system fits your project. Include your platform preference (or ask for our recommendation) when requesting a quote.

What QC data is included, and can I request additional assays?

Standard QC includes reducing SDS-PAGE, LAL endotoxin testing (<0.1 EU/µg), and — for catalytic-domain constructs — an in-vitro activity assay using a validated substrate where one exists. Additional assays beyond this panel are outside current scope; researchers needing further characterization (e.g., SEC-MALS, circular dichroism) would need to run those in-house.

What is the matched-antibody option and how does it affect the timeline?

Any custom protein produced here can serve as the immunogen for a rabbit polyclonal antibody raised in-house at TPB. Because the antibody is generated against the exact expressed construct, epitope coverage is directly traceable to the sequence you specify. The antibody track — immunization, bleeds, affinity purification, and Western blot validation — runs in parallel with protein scale-up and adds approximately 18 weeks. In practice, this means protein and antibody can be delivered within a few weeks of each other rather than sequentially.

Can I request a point mutant or an active-site knockout version of my protein?

Yes. Point mutants — including catalytic-residue substitutions — are handled at the construct-design stage. Specify the substitution(s) by standard amino-acid notation and they are introduced during gene synthesis and confirmed by sequencing before transfection begins.

Who owns the construct and sequence data generated during the project?

The expressed construct and all associated sequence data are provided to you as part of the CoA deliverable. TPB does not retain rights to your proprietary target sequence or use it for any purpose other than executing your project. Specific IP terms can be addressed in the project agreement before work begins.

Is there a small-scale feasibility step before committing to full production?

Yes — step 2 of the workflow is a small-scale expression test that confirms the construct expresses at detectable levels before scale-up is initiated. If the expression test reveals a problem (e.g., very low titre, apparent aggregation), findings are shared and options are discussed before proceeding. This checkpoint is included in the project timeline, not an add-on cost.